Men loved step dancing events (12)
I believe the answer is:
developments
'events' is the definition.
(development is a kind of event)
'men loved step dancing' is the wordplay.
'dancing' is an anagram indicator.
'men'+'loved'+'step'='menlovedstep'
'menlovedstep' with letters rearranged gives 'DEVELOPMENTS'.
(Other definitions for developments that I've seen before include "Move Len's dept (anag.)" , "Evolutions" , "MTD envelopes (anag.)" , "Progressive changes" , "Fresh events" .)